1. Field of the Invention
The instant invention is directed towards protective coatings for use on automobile surfaces and other surfaces in need of protection from foreign objects or elements. The coatings include a PVP compound or an anionic polymer dissolved in a solvent such as ethanol.
2. Description of the Prior Art
Automobiles are regularly exposed to foreign objects and elements which can be harmful to their exterior finishes. For example, in geographical regions which are subject to wintery conditions, road salt and sand are often spread on the roads in order to combat the slippery conditions. However, salt and sand can be abrasive to an automobile""s painted surface. Furthermore, the salt can promote rusting of the automobile""s metal body. Thus, people who reside in these regions must wash their cars or trucks frequently in order to attempt to lessen these problems. This can be burdensome, particularly at colder temperatures, making it very difficult for people to wash their cars or trucks unless they are willing to wait in long lines at enclosed carwashes.
Cars and trucks are also regularly subjected to flying rocks which can strike the vehicle and chip its paint. This is particularly problematic on gravel roads or near road construction areas where small rocks and debris are often xe2x80x9ckicked upxe2x80x9d by other vehicles (and particularly by large trucks) and caused to hit the car or truck traveling behind those vehicles. The only reasonable protection against this problem in the past has been the use of a so-called automobile xe2x80x9cbraxe2x80x9d fastened to the front end of the automobile. These bras consist of a large section of a durable fabric (usually black in color) having openings therein which correspond to the location of the car headlamps and grille. While these bras do assist in protecting the car from the flying rocks, they are highly visible and, therefore, undesirable to many car owners. Furthermore, automobile bras are difficult if not impossible to find in appropriate sizes and configurations for use with many vans, pickup trucks, and other large vehicles.
Another problem often encountered by automobile owners is that of insects which are struck by automobiles during travel. Insects are quite numerous during warm weather evenings, particularly in rural areas. When the insects strike the car or truck, they usually xe2x80x9csplatter,xe2x80x9d leaving behind a liquid residue on the car or truck surface which is very difficult to remove without prompt and vigorous scrubbing of the affected area, possibly requiring the use of a chemical insect remover. Even with this careful attention, some insects comprise fluids that may actually stain the paint. The solid remains of the insect can also become embedded in the car or truck surface, presenting additional cleaning problems.
In an attempt to combat this problem, some car or truck owners purchase bug shields which are installed above the grille of the car or truck. However, these shields do not protect the grille, headlamps, or bumper of the vehicle from insects, and offer only limited protection to the hood and windshield areas. Furthermore, bug shields are undesirable to many car or truck owners who do not consider them to be visually appealing.
There is a need for a method for protecting automobile surfaces from sand, road salt, insects, rocks, and other elements. The method must be essentially unnoticeable by observers, easy to use, and harmless to the automobile.
The instant invention overcomes these problems by providing a protective coating composition which lessens or prevents the problems caused by foreign elements and objects which tend to undesirably adhere to a target surface or which can damage that surface.
In one embodiment the inventive compositions are initially flowable and comprise a high molecular weight polyvinylpyrrolidone (PVP) compound dispersed in a solvent selected from the group consisting of water, alcohols, and mixtures thereof. The compositions include from about 3.5-60% by weight, preferably from about 5-15% by weight, and more preferably from about 6-10% by weight of the PVP compound, based upon the total weight of all ingredients used to form the composition taken as 100% by weight. The PVP compound should have a molecular weight of at least about 160,000 g/mol, preferably at least about 360,000 g/mol, and more preferably from about 1,100,000-2,000,000 g/mol.
As used herein, xe2x80x9cpolyvinylpyrrolidone (PVP) compoundxe2x80x9d is intended to refer to polyvinylpyrrolidone as well as functional moieties thereof. For example, the term xe2x80x9cPVP compoundxe2x80x9d would also include: 
where xe2x80x9cMxe2x80x9d is a molecule bonded to the PVP structure. Thus, xe2x80x9cpolyvinylpyrrolidone (PVP) compoundxe2x80x9d would include those moieties where any one or more of the constituents of polyvinylpyrrolidone are bonded to another molecule. The most preferred PVP compound for use in the instant is simply polyvinylpyrrolidone as represented by the structure [C6H9NO]n.
The solvent is present in the composition of this embodiment at a level of from about 40-97.5% by weight, preferably from about 60-95% by weight, and more preferably from about 85-93% by weight, based upon the total weight of all ingredients used to form the composition taken as 100% by weight. Preferred solvents include C1-C4 branched and unbranched alcohols, with ethanol and isopropanol being particularly preferred alcohols. In aqueous compositions according to the invention, the composition pH is from about 5-10.5, preferably from about 7.0-8.5, and more preferably about 7.5.
The inventive compositions should also be essentially sugar-free in order to substantially prevent rain from removing the dried compositions from the surfaces they are to protect. As used herein, xe2x80x9cessentially sugar-freexe2x80x9d means that the compositions contain less than about 0.05% by weight sugar, preferably less than about 0.02% by weight sugar, and more preferably about 0% by weight sugar, based upon the total weight of all ingredients used to form the composition taken as 100% by weight.
There are several optional ingredients that can be advantageously added to the inventive PVP-containing protective compositions. One particularly useful compound is a waterproofing agent. As used herein, xe2x80x9cwaterproofing agentxe2x80x9d refers to a compound which can be mixed with the other ingredients of the composition and which assists in inhibiting the dried composition from absorbing water. When utilized, the waterproofing agent should be included in the composition at a level of less than about 4% by weight, and preferably from about 0.2-1% by weight, with ammonium stearate and calcium stearate being particularly preferred waterproofing agents. The calcium stearate is also a flatting agent and is very useful for improving the smoothness of the composition on the target surface.
In an alternate embodiment, the inventive compositions are initially flowable and comprise (and preferably consist essentially of) an anionic polymer dispersed in a solvent. While any anionic polymer is suitable, it is preferred that the anionic polymer comprise a polyurethane (such as a polyurethane comprised of polyesterdiols, neopentyl-glycol, isophorone diisocyanate, and dimethylolpropanoic) or a polymer blend which includes at least one vinyl compound and a carboxylic acid. Preferred vinyl compounds include butyl acrylamides and vinyl esters such as vinyl acetate, ethyl acrylate, and vinyl neodecanoate. Preferably, the blend comprises two such vinyl compounds (e.g., ethyl acrylate and a butyl acrylamide or vinyl acetate and vinyl neodecanoate).
The carboxylic acid preferably comprises a C3-C14, and more preferably C3-C6, branched or unbranched hydrocarbon group. Preferred carboxylic acid include those selected from the group consisting of crotonic acid, acrylic acid, and dimethylolpropanoic acid.
A particularly preferred anionic polymer blend includes from about 1-10% by weight vinyl acetate, from about 40-80% by weight carboxylic acid, and from about 30-50% by weight vinyl neodecanoate, based upon the total weight of the polymer blend taken as 100% by weight. The anionic polymer blend is formed by simply forming a mixture of the various ingredients described above. A preferred anionic polymer blend is available from BASF Aktiengesellschaft in Germany under the name Luviset CAN(copyright).
Preferred solvents for dispersing the anionic polymer include C1-C4 branched and unbranched alcohols such as methanol, ethanol, propanol, isopropanol, and butanol. The protective compositions of this embodiment should include from about 3-40% by weight polymer blend, preferably from about 10-25% by weight polymer blend, and more preferably from about 15-20% by weight polymer blend, based upon the total weight of the protective composition taken as 100% by weight. The solvent should be mixed with the polymer blend at a level of from about 60-97% by weight, preferably from about 75-90% by weight, and more preferably from about 80-85% by weight, based upon the total weight of the protective composition taken as 100% by weight.
Other optional ingredients which can be incorporated into the inventive compositions (regardless of the embodiment) include flow agents, drying agents, defoaming agents, fisheye preventatives (e.g., silicone fluids), fragrances, and coloring agents. A surfactant can be included in the PVP-containing embodiment when water is the major solvent present in the composition. When used, the surfactant should be present at a level of less than about 3% by weight, and preferably less than about 1% by weight, based upon the total weight of all ingredients used to form the composition taken as 100% by weight. Suitable surfactants include benzalkonium chloride, benzethonium chloride, sodium lauryl sulfate, and a surfactant sold under the trade name TERGITOL(trademark) (available from Union Carbide).
The inventive compositions are formed by simply mixing the ingredients (either the PVP compound or the polymer blend), solvent(s), and other optional ingredients for about 5-10 minutes until a uniform dispersion is obtained. In order to effect uniform mixing, the ingredients can be heated to a temperature of from about 105-115xc2x0 F., if desired. Heating to this temperature is preferred if calcium stearate is one of the ingredients.
In an alternate embodiment, the composition can be formulated into an aerosol utilizing known propellants (e.g., propane or butane). In aerosol embodiments, the PVP compound comprises from about 2-15% by weight, and preferably from about 5-10% by weight of the total aerosol product, while the solvent comprises from about 37-75% by weight, and preferably from about 45-48% by weight of the total aerosol product. The remainder of the product will generally be propellant. Of course, those skilled in the art will appreciate that the concentrations of the ingredients in the aerosol products can be altered to accommodate the use of the optional ingredients as described above.
In application, a quantity of the inventive composition is simply applied (e.g., by spraying, by brushing, etc.) to the target surface. Preferably, the composition is applied in a thin coat of from about 1-3 mm in thickness. This coat should be allowed to dry (about 10 minutes) prior to normal use of the surface. However, while one layer may be sufficient in some applications, it is generally preferred to apply two to three layers of the composition, allowing each layer to dry prior to the addition of a subsequent layer. As a result of this multiple coating process, the combined thickness of all coats of the composition on the surface should be from about 3-6 mm about 10 minutes after application of the final layer.
The instant composition has a significant advantage over the prior art in that it can be applied under ambient conditions (including high humidity environments such as 60% HR or higher, and/or cold temperatures such as 20xc2x0 F. or lower). Furthermore, upon drying, the inventive compositions form a protective coating that is harder than prior art coatings. That is, the hardnes of the dried coating is at least about 70, and preferably at least about 80, as determined by ASTM D2240-97 (durometer A).
The inventive compositions are safe and effective for protecting many different surfaces. For example, the compositions can be applied to vulnerable portions of an automobile""s exterior (e.g., to the grills, chrome, headlamps, hood, and/or front end of the automobile) in order to protect those surfaces from contact with undesirable elements such as acid rain, sand, road salt, insects (which can become embedded in the paint), and rocks (which may chip the paint). Additionally, the compositions can be applied to windows (e.g., house windows, automobile windows, etc.) to protect them from overspray during a painting process. Finally, while the dried coatings provide significant protection against insects and rocks which may come into contact with the protected surface, the PVP coating can be readily removed with high pressure water, or with detergent in water in those situations where a waterproofing agent is utilized. The anionic polymer coating can be removed by applying a remover solution (see Table 1) to the coating followed by rinsing the surface with water or wiping it clean.